Compartmented tray reinforced against bending



E. L. SMlTH 3,502,241

COMPARTMENTED TRAY REINFORCED AGAINST BENDING March 24. 1970 3 Sheets-Sheet 1 Filed March 25, 1968 VN I NN INVENTOR.

E L SMITH A TTORNE Y5 March 24, 1970 E. SMITH COMPARTMENTED TRAY REINFORCED AGAINST BENDING Filed March 25, 1968 i 3 Sheets-Sheet 2 INVENTOR. E. L. SMITH ATTORNEYS E. L. SMITH 3,502,241

COMPARTMENTED TRAY REINFORCED AGAINST BENDING March 24. 1970 5 Sheets-Sheet 5 Filed March 25, 1968 FIG. 6

INVENTOR. E. L. SMITH ATTORNEYS 3,502,241 COMPARTMENTED TRAY REINFORCED AGAINST BENDING Ernest L. Smith, Kansas City, Mo., assignor to Phillips Petroleum Company, a corporation of Delaware Filed Mar. 25, 1968, Ser. No. 715,776

Int. 'Cl. A01c 11/00; B65d 21/02, 1/34 U.S. Cl. 22023.6 10 Claims ABSTRACT OF THE DISCLOSURE ,In a thermoformed tray containing rows of compartments, each pair of adjacent rows is joined by an inverted U-shaped reinforcing member and each pair of adjacent compartments within a row is joined by an inverted U- shaped divider member. The peripheral wall of the tray has a height greater than the height of each reinforcing member, which in turn is greater than the height of the divider members. The ends of each reinforcing member and the peripheral ends of the divider members are inclined upwardly from the remainder of the respective members to join the tray peripheral wall. A portion of the bottom wall of each compartment is raised to provide a support surface. Off-center stacking lugs are provided in each reinforcing member.

Thermoformed trays have been proposed for many uses, but in general have been restricted to bearing relatively light loads. This has been particularly true for compartmented trays wherein the compartments are in alignment due to the small resistance to bending along the line of compartment separators. It is an object of the invention to provide a thermoformed tray which can support heavy loads. It is an object of the invention to provide a compartmented thermoform tray with improved resistance to bending. Other objects, aspects, and advantages of the invention will be apparent from a study of the specification, the drawings and the appended claims to the invention.

In the drawings FIGURE 1 is a plan view of a compartmented tray in accordance with one embodiment of the invention; FIGURE 2 is a front elevational view, partly in cross section, taken along line 2-2 in FIGURE 1; FIGURE 3 is a side elevational view, partly in cross section, taken along line 33 in FIGURE 1; FIGURE 4 is a partial view in cross section taken along line 44 in FIGURE 1; FIGURE 5 is a partial view in cross section taken along line 5-5 in FIGURE 1 with rectangularly shaped seedling pots positioned in the tray compartments; and FIGURE 6 is a partial view in cross section taken along line 6-6 in FIGURE 1 with the rectangularly shaped seedling pots positioned in the tray compartments.

Referring now to the drawings in detail, tray 11 is thermoformed from a sheet of thermoplastic material, for example, a homopolymer or copolymer of at least one mono-l-olefin having up to ten carbon atoms per molecule such as polyethylene, polypropylene, ethylenebutene copolymer, or ethylene-hexene copolymer; polystyrene; poly(vinyl chloride); and the like. Tray 11 has two rows of compartments which are substantially rectangular in horizontal cross section, with compartments 12a, 13a, 14a, 15a and 16a being the first row and compartments 12b, 13b, 14b, 15b and 16b being the second row. Each adjacent pair of compartments in a row is separated by a divider member which is substantially inverted U-shaped in cross section. Thus, compartments 12a and 13a are separated by divider member 17a, compartments 13a and 14a by divider member 18a, compartments 14a and 15a by divider member 19a, and compartment 15a and 16a by divider member 20a. Similarly, divider mem- United States Patent 0 F 3,502,241 Patented Mar. 24, 1970 ice bers 17b, 18b, 19b and 20b separate adjacent pairs 12b and 13b, 13b and 14b, 14b and 15b, and 15b and 16b. Divider members 17a, 18a, 19a and 20a are colinear with divider members 17b, 18b, 19b and 20b, respectively, Which separate the corresponding adjacent compartments in the other row. This colinear relationship presents a situation of only nominal resistance against bending along the line of colinear divider members. In the absence of reinforcing features, any significant weight, sometimes even just the weight of the tray, could cause folding. In accordance with the invention, reinforcing member 21, which joins together the adjacent pair of rows of compartments, has a height greater than the height of the divider members, as illustrated in FIGURES 2 and 3. This provides a reinforcing structure transverse to each set of colinear divider members, thus aiding in strengthening the tray against bending. As illustrated in FIG- URES 1 and 2, the reinforcing member 21 extends continuously from one end of tray 11 to the opposite end of tray 11. Also, in accordance with the invention, the outer ends of divider members 17a, 18a, 19a, 20a, 17b, 18b, 19b and 20b and the compartment walls which are on the periphery of the tray as well as the ends of reinforcing member 21, extend upwardly to form an upstanding side wall 22 having a height greater than the height of reinforcing member 21, and thus also greater then the height of divider members 17a-20a and 17b20b. This provides a reinforcing structure transverse to the outer end of each of the divider members, thereby strengthening the tray against bending along the line of colinear divider members. This also provides a reinforcing structure transverse to the ends of reinforcing member 21, thereby giving resistance to bending along the line of reinforcing member 21. In accordance with a presently preferred embodiment of the invention, an inverted U- shaped rim 23 is formed in combination with wall 22 by flange 24 extending outwardly from the upper end of Wall 22 and flange 25 extending downwardly from the outer end of flange 24. Rim 23 extends around the entire periphery of wall 22.

The reinforcing structure of tray 11 is further enhanced by the ends of the reinforcing member 21 and the ends of the divider member which intersect wall 22 being inclined upwardly from the remainder of the respective member. Thus, reinforcing member 21 is provided with inclined end portions 26 and 27, and divider members 17a, 18a, 19a 20a, 17b, 18b, 19b and 20b are provided with inclined end portions 31, 32, 33, 34, 35, 36, 37 and 38, respectively. The inclined portions not only aid in resisting bending of the tray along the longitudinal axis of the reinforcing member 21 and the longitudinal axis of a pair of colinear divider members, but also increase the resistance to bending in the transverse direction.

The central portion 40, 41, 42, 43, 44, 45, 46, 47, 48 and 49, 'of the bottom surface of each of compartments 12a, 13a 14a 15a, 16a, 12b, 13b, 14b, 15b and 16b, respectively, is raised above the remainder of the compartment bottom wall surface to form in each compartment a support surface surrounded by a depressed area. Where the upstanding walls of the raised portions are substantially vertical and of sufficient height so that the dimensions of the top surface of each raised portion are greater than the corresponding dimensions of the opening in the bottom of the tray formed by the raised portions, the raised portions can serve as stacking lugs. However, where the upstanding walls of the raised portions are not of sufiicient height or substantially vertical, stacking lugs 51 and 52 can be formed as depressions in reinforcing member 21, as illustrated in FIGURES l, 2, 3 and 4. Stacking lugs 51 and 52 are formed in member 21 at different distances from the ends of the member 21, enabling nesting when lug 51 is placed over lug 51 of a like 3 tray and causing stacking when one of the trays is rotated 180.

Referring now to FIGURES 5 and 6 containers 61, 62 and 63 have been placed in compartments 12b, 13b and 12a, respectively. Containers 61, 62 and 63 have a cross section corresponding to but slightly smaller than the cross section of the compartments. The bottom of each of the containers 61, 62 and 63 rests upon the support surface formed by raised portions 45, 46 and 40, respectively. Each of containers 61, 62 and 63 is provided with indented side panels 64 and indented end panels 65.

In one particular application containers 61, 62 and 63 are seedling containers and tray 11 is utilized as a flat to hold and/or transport a plurality of the seedling containers. In this use, each of containers 61, 62 and 63 can be provided with at least one opening 66 in that portion of the bottom surface of the container which overlies the depressed area around the support surface. Thus, in FIGURE 6, opening 66 is spaced from the raised portion 45. This permits the seedlings to be Watered, with the excess water draining through the opening 66 into the depressed area. Subsequent vaporization of this excess water aids in maintaining a moist environment for the seedlings.

While tray 11 has been illustrated with two rows of compartments, any desired number of rows can be employed, with a reinforcing member 21 joining each pair of adjacent rows. Similarly, while tray 11 is shown with five compartments in each row, any desired number of compartments can be utilized. While a substantially rectangular cross section is presently preferred for each compartment, trays containing other configurations, for example, substantially oval, can be fabricated in accordance with the invention. Other stacking means can be utilized instead of or in addition to lugs 51 and 52.

I claim:

1. A compartmented tray thermoformed from a sheet of thermoplastic material and having at least two rows of compartments, adjacent compartments in each row being separated by divider members which are colinear with the divider members which separate the corresponding adjacent compartments in the other rows, a reinforcing member extending continuously from one end of the tray to the opposite end of the tray joining each pair of adjacent rows, each said divider member and each said reinforcing member being substantially inverted U-shaped in cross section, the height of each said reinforcing member being greater than the height of said divider members to provide a reinforcing structure transverse to each set of colinear divider members to strengthen the tray against bending, the divider member ends and the compartment walls which are on the periphery of the tray and the ends of each said reinforcing member extending upwardly to form an upstanding side wall having a height greater than said divider members and each said reinforcing member to provide a reinforcing structure transverse to the outer end of each divider member connected to said side wall to strengthen the tray against bending along the line of colinear divider members and to provide a reinforcing structure transverse to the outer ends of each said reinforcing member for resisting bending along the line of each said reinforcing member.

2. A compartmented tray in accordance with claim 1 wherein a portion of the bottom surface of each of said compartments is raised above the remainder of the compartment bottom surface.

3. A compartmented tray in accordance with claim 2 wherein said portion is the central portion of each compartment bottom surface to form in each compartment a support surface surrounded by a depressed area.

4. A compartmented tray in accordance with claim 1 wherein first and second stacking depressions are formed in each said reinforcing member at different distances from the ends of the respective reinforcing member.

5. A compartmented tray in accordance with claim 1 wherein each end of a divider member which intersects said upstanding side wall and each end of each said reinforcing member is inclined upwardly from the remainder of the respective divider member or reinforcing member to join said upstanding side wall, thereby forming a reinforced structure to resist bending along the line of each reinforcing member and along the line of colinear divider members and in a direction transverse to the respective divider member and the respective reinforcing member.

6. A compartmented tray in accordance with claim 5 wherein each of said compartments is substantially rectangular in horizontal cross section.

7. A compartmented tray in accordance with claim 6 wherein a portion of the bottom surface of each of said compartments in raised above the remainder of the compartment bottom surface.

8. A compartmented tray in accordance with claim 7 wherein said portion is the central portion of each compartment bottom surface to form in each compartment a support surface surrounded by a depressed area.

9. A compartmented tray in accordance with claim 8 wherein first and second stacking depressions are formed in each said reinforcing member at different distances from the ends of the respective reinforcing member, and wherein an inverted U-shaped rim extends outwardly and downwardly from the upper end of said upstanding side wall.

10. A compartmented tray in accordance with claim 9 further comprising a container having a cross section corresponding to but slightly smaller than the cross section of one of said compartments positioned on the support surface in said one of said compartments, said container having at least one Opening in the bottom surface thereof spaced from the respective support surface.

References Cited UNITED STATES PATENTS 2,743,030 4/1956 Read 22021 3,142,133 7/1964 Brooks 4737 3,386,608 6/1968 Diller 22023.6 3,224,569 12/1965 Leitzel 229--2.5 X 3,362,561 1/1968 Bakos 220-21 GEORGE T. HALL, Primary Examiner US. Cl. X.R. 

